How do you know when its a noun, pronoun and adjective?

noun is person, place, or thing

pronoun is used for a person in place of their name (he, she, they, xem, etc.) like instead fo saying, "Sam went to the store. Sam enjoyed it very much" you can say "Sam went to the store. <<He>> enjoyed it very much."

adjective describes things like, "that was a <<delicious>>> apple" or "the kitten is very <<fluffy>>"

cavern or cave

i hope this

you did not put the article. so i cannot answer the question.